Doctors call these liver enzymes in the blood, liver function tests or LFTs. The most important LFTs are ALT, AST, alkaline phosphatase (AP), and bilirubin.

There are many causes of elevated LFTs, such as chronic viral hepatitis B and C, inflammation related to alcohol (alcoholic hepatitis), and cancer. Medical tests would be necessary to diagnose the cause of the abnormal LFTs and fatigue, such as more blood tests, scan of the abdomen and liver, and liver biopsy.

A living tissue, our blood delivers oxygen to our organs, fights infections and prevents us from bleeding excessively when a blood vessel is damaged.
Our red and white blood cells and platelets are created in the soft, squishy material found inside our bones, called bone marrow. They make up about half the solid substances found in our blood, which travels through our bodys arteries and veins. The other half of our blood consists of a yellowish liquid called plasma, which carries red blood cells, nutrients, proteins, hormones and waste products.
Red blood cells contain hemoglobin, a protein that releases oxygen to tissues as it travels in our blood vessels. White blood cells travel in and out of our bloodstream to fight germs, while platelets work with substances called clotting factors to keep us from bleeding to death when we are injured.
With more than a gallon of blood circulating in our body, we can be affected by more than a dozen blood disorders, such as anemia and hemophilia.